Optical Sound Examples

The major commercial use of optical sound on film started in the late 1920s. In its simplest form, optical sound is just flickering the light from a light bulb, similar to waving a hand in front of a flashlight. The light being modulated by the recording is turned into electrical sound signals via a phototube or photodiode. Although seemingly crude, optical sound is at the core of motion picture sound and saw decades of intense research and development. From the first optical sound feature in 1927 through the stereo prints of Star Wars, over a dozen different optical sound formats have been used with incredible results. Each optical format, though, has its own unique sound attributes and challenges.